The present invention generally relates to drug delivery systems and other polymeric products that they can be disposed of after use by flushing into a toilet.
Transdermal drug delivery systems are now commonly used to deliver a variety of types of drugs across the skin. Transdermal delivery systems are particularly useful for the delivery of drugs with low molecular weights and high water solubility, and offer some advantages over other delivery systems. For example, these systems deliver drugs directly to the systemic circulation, by-passing problems sometimes associated with first pass metabolism. The systems are also useful for delivering drugs in a steady-state manner, without producing highs and lows in blood levels, and for providing prolonged delivery times. Examples of transdermal drug delivery systems include formulations designed to deliver anti-anginal glyceryl trinitrate (nitroglycerin), formulations designed to deliver nicotine for smoking cessation, and formulations for hormone replacement therapy (HRT) to treat menopausal symptoms and prophylaxis of osteoporosis. These products are sold under tradenames such as DEPONIT(trademark), DUROGESIC(trademark), ESTRACOMBI(trademark), ESTRADERM(trademark), ESTRAPAK(trademark), EVOREL-PAK(trademark), EVOREL(trademark), FEMATRIX(trademark), MINITRON(trademark), NICONIL(trademark), NICORETTE(trademark), NICOTINEL(trademark)L, NITRO-DUR(trademark), NITROLINGAL(trademark), SCOPODERM(trademark), and TRANSIDERM-NITROR(trademark).
The initial transdermal patches used one of three approaches to deliver drugs: membrane permeation, multilaminate adhesive dispersion and matrix dispersion. In all three cases the physical appearance of the dosage form resembles an adhesive plaster dressing. The difference in the delivery approach lies in the technique used to retain the drug and control its release. In the membrane permeation approach, a flat packet made with one wall of a drug-impermeable laminate and a second wall made from a rate-controlling membrane is used to hold a reservoir of drug. The membrane is coated externally with a pressure sensitive adhesive polymer which is drug compatible. In the second approach, the drug is contained in an adhesive polymer and is sandwiched between a drug-impermeable backing support and thin layers of rate-controlling adhesive forming a multilaminate adhesive dispersion. In the matrix diffusion approach, the drug is homogeneously dispersed in a matrix molded in a disc of predefined surface area and thickness.
Improvements in the use of transdermal systems continue to be made, for example, with the use of skin penetration enhancers, electrotransport, as well as systems to deliver different drug types, such as insulin for diabetics, and prostaglandins for treatment of peripheral arterial occlusive disease.
One disadvantage to the use of transdermal drug delivery patches relates to the potential hazards associated with their disposal after use. At the end of their use these transdermal drug delivery patches must be safely discarded. This can be a particular concern if no suitable collection system exists and the patch contains residual active ingredients and/or has become contaminated during use, for example, with bodily fluids. The problem is further compounded by the frequency of use of these patches. Many patches, for example, are applied daily for prolonged periods of time. There is also a further complication involved in disposing of those devices which incorporate electrotransport systems, for example, as described in U.S. Pat. No. 5,879,322 to Lattin, et al.
A potentially good method for disposing of transdermal drug delivery patches (and other drug contaminated devices, including simplier devices such as BAND-AID(trademark) plastic adhesive bandages) in a safe and environmentally acceptable manner could involve flushing these patches down the toilet after use. Unfortunately, while the physical and chemical properties of the components of the current transdermal drug delivery vehicles make them well suited to their task of drug delivery, these components are generally derived from materials which will not degrade in water or sewage. Such disposal could lead to blockages in the sewerage system or subsequent contamination.
It is therefore desirable to have flushable transdermal drug delivery systems which are easier to use and can be disposed of in a safe and environmentally acceptable manner. It is also desirable to have other types of flushable drug delivery systems for the same reasons, including systems used for buccal, vaginal and ophthalmic delivery of drugs, as well as adhesive bandages and coverings.
It is therefore an object of this invention to provide components for preparing flushable drug delivery systems and adhesive bandages.
It is a further object of this invention to provide methods for fabricating flushable drug delivery systems and bandages.
Biodegradable polyhydroxyalkanoate materials suitable for preparing components of flushable drug delivery systems and bandages are described. These components include drug impermeable and drug permeable materials, including materials that can be used to control the rate of release of drugs from the device, and pressure sensitive adhesive compositions which are drug and/or skin compatible. Methods for fabricating these devices, including transdermal drug delivery patches, are described.